Boysen’s (www.boysen-online.de) dual-line, valve-controlled exhaust system—mated to BMW’s 4.4-liter twin-turbo V8 engine—reduces noise and improves power output through the use of two close-coupled ceramic catalytic converters, two front silencers, a middle silencer—with integrated pressure equalization—and two rear silencers in each of the two tailpipes.

Boysen’s (www.boysen-online.de) dual-line, valve-controlled exhaust system—mated to BMW’s 4.4-liter twin-turbo V8 engine—reduces noise and improves power output through the use of two close-coupled ceramic catalytic converters, two front silencers, a middle silencer—with integrated pressure equalization—and two rear silencers in each of the two tailpipes. During low-speed operation, the exhaust valves on the two inner tailpipes remain closed to reduce noise, while the valves are opened pneumatically at higher-speed operation to increase the pipe cross-section, reduce backpressure, which results in improved engine power output.